A report by KPRC says the study compared the average amount of debt against the median income in 25 of the nation’s largest cities to come up with the list. The highest debt burdens were found when credit card balances were found to be high and earnings were at the average level or lower.

The study found the typical San Antonio resident, using 15 percent of their monthly income, took almost two years to pay off the amount of an average worker’s credit card balance.

By contrast, the typical San Fransisco worker only needed about 13 months.

Income disparities contribute to how much debt the average person in a given city takes on. In San Fransisco, people are earning more than the average resident of San Antonio, so they can pay down their debt more quickly.

In Houston, the average time it takes to pay off a credit card balance is 20 months.

Economic backgrounds and status also affect people’s views on credit and banking, and may have an impact on their level of debt as well, according to the study.

Some cities that don’t earn as much, like Detroit, were still able to keep their card balances at a manageable level. The study points to the city as a good example, cautioning people to be responsible with their cards and moderate their use of credit.

Melinda Opperman, executive vice president of credit.org, surmised:

The new record high credit card use is seen by some as a sign of confidence in the economy, but more debt is more potential for financial hardship – especially during times of unemployment and times of reduced income. It is important for consumers to have an emergency savings account to weather these setbacks.